As a device which uses a change in resistance (change in magneto-resistance) based on a change in a relative angle of magnetization of two ferromagnetic layers, a giant magneto-resistance (GMR) device formed of a multi-layer film including a ferromagnetic layer and a non-magnetic layer, a tunneling magneto-resistance (TMR) device in which an insulating layer (a tunneling barrier layer, a barrier layer) is used for a non-magnetic layer, and the like are known.
MRAM reads and writes data using characteristics that a device resistance of a GMR device or a TMR device changes when the directions of magnetization of two ferromagnetic layers having an insulating layer disposed therebetween change. As a writing method of MRAM, a method of performing writing (magnetization reversal) using a magnetic field created by a current and a method of passing current in a stacking direction of magnetoresistance effect elements to perform writing (magnetization reversal) using a spin-transfer torque (STT) generated by the current are known.
In magnetization reversal of a magnetoresistance effect element using an STT, it is necessary to pass a current in a stacking direction of the magnetoresistance effect elements when writing data. A writing current may sometimes cause the characteristics of magnetoresistance effect elements to deteriorate.
Therefore, in recent years, methods which do not require passing a current in a stacking direction of magnetoresistance effect elements during writing have drawn attention. One of these methods is a writing method which uses a spin-orbit torque (SOT) (for example, see Non-Patent Literature 1). An SOT is induced by a pure spin current generated by the spin-orbit interaction or by the Rashba effect at the interface between different materials. A current for inducing an SOT in a magnetoresistance effect element is passed in a direction crossing the stacking direction of magnetoresistance effect elements. That is, since it is not necessary to pass a current in the stacking direction of these magnetoresistance effect elements, the service life of the magnetoresistance effect elements is expected to be able to be extended.